1. Field of the Invention
The present invention relates generally to abrasion resistant polyurethane coatings, and more particularly to a method for applying thin polyurethane coatings.
2. Discussion of the Technology
U.S. Pat. No. 4,079,160 to Phillipson teaches an optical element, such as an eyeglass lens, formed of a typical rigid polymeric substrate of relatively low scratch resistance coated on at least one surface with a relatively soft, resilient and tough, transparent polymeric material. Spinning techniques are disclosed to be particularly suitable for applying the coating to the lens.
U.S. Pat. No. 4,174,240 to Muller teaches laminates wherein glass or glass-like plastics are coated with a transparent film 0.1 to 5 millimeters thick formed from a polyurethane polyurea containing 1 to 20 percent by weight urea groups and 0.001 to 10 percent by weight lateral --COOH groups. The polyurethane polyurea films are formed by solution casting or extrusion and are subsequently laminated to the substrates by the application of heat and pressure.